The chemical formula of gypsum is-

Gypsum is an ore of Calcium (Ca). The chemical formula of Gypsum is CaSO4.2H2O
-Gypsum is mainly used as a fertilizer, as the main constituent in plaster, chalk, etc.
-Rapid setting of cement is the function of gypsum in cement.
-It is a crystalline mineral composed of calcium sulfate dihydrate.
-Gypsum helps in controlling the rate of hardening of the cement.
-It also prevents early hardening allowing long working time, hence we can say that it helps in the rapid setting of cement.
-The Bikaner district of Rajasthan has the maximum quantity of Gypsum.
-Rajasthan produces 90% of total production in India.